Fig. 4
CMR and exercise CMR imaging protocols. A Our technique was first evaluated at rest, which consisted of breath-hold, electrocardiogram (ECG)-segmented tagging followed by free-breathing real-time tagging. The real-time acquisition was repeated once to assess repeatability. B Feasibility of real-time tagging imaging with physiology stress was evaluated in subjects prospectively recruited for exercise CMR. Real-time tagging images were collected pre- and post-exercise. Subjects were exercised in the supine position using a cycle ergometer. Work rate was started at Ω0 = 10W, 15W, 20W or 25W, and was increased by ∆Ω0 = + Ω0 every 2 min while subjects maintained a constant pedaling speed of 75 rpm. After 10 min or exhaustion, subjects were immediately transferred for post-exercise stress imaging. This consisted of a repetition of the real-time tagging sequence